chrome/browser/network_time/network_time_service.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/network_time/network_time_service.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/prefs/pref_service.h"
   9 #include "chrome/browser/network_time/network_time_tracker.h"
  10 #include "chrome/browser/profiles/profile.h"
  11 #include "chrome/common/chrome_switches.h"
  12 #include "chrome/common/pref_names.h"
  13 #include "components/user_prefs/pref_registry_syncable.h"
  14
  15 // static
  16 void NetworkTimeService::RegisterProfilePrefs(
  17     user_prefs::PrefRegistrySyncable* registry) {
  18   registry->RegisterDictionaryPref(
  19       prefs::kNetworkTimeMapping,
  20       new base::DictionaryValue(),
  21       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
  22 }
  23
  24 NetworkTimeService::NetworkTimeService(Profile* profile)
  25     : profile_(profile) {
  26   if (!CommandLine::ForCurrentProcess()->HasSwitch(
  27       switches::kEnableNetworkTime)) {
  28     return;
  29   }
  30
  31   network_time_tracker_.reset(new NetworkTimeTracker);
  32   network_time_tracker_->Start();
  33
  34   const base::DictionaryValue* time_mapping =
  35       profile_->GetPrefs()->GetDictionary(prefs::kNetworkTimeMapping);
  36   double local_time_js;
  37   double network_time_js;
  38   if (time_mapping->GetDouble("local", &local_time_js) &&
  39       time_mapping->GetDouble("network", &network_time_js)) {
  40     base::Time local_time_saved = base::Time::FromJsTime(local_time_js);
  41     if (local_time_saved > base::Time::Now() ||
  42         base::Time::Now() - local_time_saved > base::TimeDelta::FromDays(7)) {
  43       // Drop saved mapping if clock skew has changed or the data is too old.
  44       profile_->GetPrefs()->ClearPref(prefs::kNetworkTimeMapping);
  45     } else {
  46       network_time_tracker_->InitFromSavedTime(
  47           NetworkTimeTracker::TimeMapping(
  48               local_time_saved, base::Time::FromJsTime(network_time_js)));
  49     }
  50   }
  51 }
  52
  53 NetworkTimeService::~NetworkTimeService() {}
  54
  55 void NetworkTimeService::Shutdown() {
  56   if (!network_time_tracker_)
  57     return;
  58
  59   if (network_time_tracker_->received_network_time()) {
  60     // Update time mapping if tracker received time update from server, i.e.
  61     // mapping is accurate.
  62     base::Time local_now = base::Time::Now();
  63     base::Time network_now = GetNetworkTime(local_now);
  64     base::DictionaryValue time_mapping;
  65     time_mapping.SetDouble("local", local_now.ToJsTime());
  66     time_mapping.SetDouble("network", network_now.ToJsTime());
  67     profile_->GetPrefs()->Set(prefs::kNetworkTimeMapping, time_mapping);
  68   }
  69 }
  70
  71 base::Time NetworkTimeService::GetNetworkTime(
  72     const base::Time& local_time) {
  73   if (!network_time_tracker_.get() || local_time.is_null() ||
  74       local_time.is_max())
  75     return local_time;
  76
  77   base::Time network_time_now;
  78   if (!network_time_tracker_->GetNetworkTime(base::TimeTicks::Now(),
  79                                              &network_time_now, NULL)) {
  80     return local_time;
  81   }
  82   return local_time + (network_time_now - base::Time::Now());
  83 }
  84
  85 base::Time NetworkTimeService::GetNetworkNow() {
  86   return GetNetworkTime(base::Time::Now());
  87 }